This one specifically target's "how-to" content. Via NBC: http://www.nbcnews.com/tech/internet/googles-phantom-algorithm-update-hits-websites-n358346
From that article: So basically Google is stealing other websites' information and displaying it on its own search page so people do not have to click through to other sites. Then Google trashes those sites in the rankings so they will have to pay Google for advertising if they want to replace the lost traffic. Classic Google greed.
This may be true, but i think not to be 100%, because google add a official search link below there guide, just like in Thumbnail. So you can't say they are stealing something from your site.